Our project is a new 7-story, 120-unit, residential building for retired seniors in Massachusetts. The apartments will have operable windows in the living rooms and bedrooms, with openable areas significantly greater than 4% of the floor area, and kitchens that are permanently open to the living rooms. However, some apartments will be deeper than 25 feet. (The worst case scenerios would likely be 29 feet deep for a non-corner unit or 38 feet deep for a corner unit.) Furthermore, some units will have interior bathrooms and walk-in closets that are not permanently open (as defined by ASHRAE 62.1 2004) to the spaces with windows. The living units will have heat pumps with air handlers that offer heating, cooling, or fan-only mode. The air handlers will intake return air, rather than outside air, but the air intake will be within 25 feet of the operable windows, meaning a portion of the air would be fresh when the windows are open. The air handlers would then distribute ducted supply air to each major room, not including bathrooms and walk-in closets. Also, the public corridors will be positively pressurized providing make-up air to the apartments via door under-cuts. The bathrooms will have occupant-controlled exhaust fans. 1. Is it possible that this design as-is meets the outdoor air ventilation requirements of ASHRAE 62.1 2004? If so, with such a complex air delivery model, how do we perform the calculations, if any, to prove this for LEED? 2. If it sounds like our design does not meet ASHRAE 62.1 2004, could either of the following solutions bring us into compliance? And again how would we perform the calculations, if any? a. Installing occupant-controlled paddle fans on the ceilings of the rooms with windows. b. Installing continuous bathroom exhausts (or bathroom exhausts on a timer) to draw fresh air deeper into the space. The bathrooms are usually located at the furthest points from the operable windows. 3. If none of the above solutions sound like they meet ASHRAE 62.1 2004, do you have any suggestions other than making the living units less than 25 feet deep? By the way, we would like to keep the units negatively pressurized with respect to the public corridors to meet the Environmental Tobacco Smoke prerequisite. One final question. Under ASHRAE 62.1 2004 are apartment kitchens required to be exhausted to the outdoors? If so, is there any way the bathroom exhausts could satisfy this requirement?
This CIR poses three questions. The first question is whether the design described in the Credit Interpretation Request, where some spaces fall further than 25 feet from an operable window, meet the ASHRAE Standard 62.1-2004 minimum ventilation requirements. Based on a previous CIR (EQp1 Ruling date 5/15/2007) if the HVAC system is re-circulating air only, then the unit is considered naturally ventilated provided that it meets the requirements laid out in section 5.1 of the Standard. If all requirements for a naturally ventilated space are met then that space complies with the requirements of the Standard for naturally ventilated spaces. If a space is further than 25 feet from an operable window it cannot be considered as naturally ventilated. Since the depth of some residential units in this project is more than 25 feet from operable windows, it is possible that not all spaces in this project can be considered naturally ventilated. In order to ensure compliance with the ASHRAE Standard\'s minimum ventilation requirements for mechanically ventilated spaces, the project team will have to refer to Appendix E of the standard which applies to residential and healthcare projects. Appendix E provides guidance on adequate ventilation rates through air changes per hour and/or cfm per person outdoor air ventilation rates (for living areas), and cfm exhaust (for bathrooms and kitchens). Note that walk-in closets are excluded from the Standard, since they cannot be considered as "occupiable space" by the Standard\'s definition (page 4 of ASHRAE Standard 62.1-2004). The design described does not comply with the requirements of Appendix E, since the ventilation system described is re-circulation only. Calculations to demonstrate compliance with ASHRAE Standard 62.1-2004 for naturally ventilated spaces will include showing adequate operable window opening area, and/or permanently open area to another space that is naturally ventilated (the total areas of both spaces have to be included in the 4% operable window opening area calculations). Calculations to demonstrate compliance with ASHRAE Standard 62.1-2004 for mechanically ventilated spaces in residential projects, will include showing air changes per hour and/or cfm per person outdoor air ventilation rates (for living areas), and cfm exhaust (for bathrooms and kitchens), according to the requirements of Appendix E. The second question proposes two methods to ensure compliance with ASHRAE Standard 62.1-2004 minimum ventilation rates in spaces that cannot be classified as naturally ventilated. The first proposed method, installing occupant-controlled paddle fans on the ceilings of rooms with operable windows, will not ensure adequate ventilation in spaces that are outside of the 25 feet range from the operable window. Even if the project team can demonstrate that adequate air changes per hour has been achieved in those spaces, this requires the paddle fan to be constantly in operation. The second proposed method, installing continuous bathrooms exhausts (or bathroom exhaust on a timer), will only ensure that the bathrooms will meet the requirements of Appendix E and will not have an impact on other spaces. The other option would be to provide the required amount of fresh air into occupiable areas more than 25 feet from the windows, in order to meet the requirements of Appendix E. The third question is asking whether under ASHRAE 62.1 2004, kitchens are required to be exhausted to the outdoors. If the kitchens qualify as naturally ventilated spaces, and there are no special requirements for combustion air or removal of combustion products, then there is no exhaust requirement. If the kitchens do not qualify as naturally ventilated spaces, then they will have to meet the exhaust requirements laid out in Appendix E: 100 cfm intermittent or 25 cfm continuous exhaust.